Audio in the chat room would be misleading... unless everyone had an equal connection to the internet. Not to mention everyone talking over each other when it was crowded.
Skype is nice if you have highspeed internet...
And we used to use something called Teamspeak which could be applied here... but it was awkward and unpleasant often. As well it was tricky to hook up, and not everyone made it "into" the chats.
Remember, wherever you go... there you are.